Gleevec (imatinib)

Gleevec® (imatinib) treats advanced melanoma with c-KIT mutations. It is used when the melanoma:1

  • Cannot be removed with surgery (unresectable) or
  • Has spread to distant parts of the body (metastasized)

The US Food and Drug Administration approves drugs for certain uses. They make these decisions based on the results of large clinical trials. Gleevec is approved for certain types of blood cancer and blood cell disorders, soft tissue cancer (sarcoma), and gastrointestinal stromal tumors.2

Gleevec is not approved for melanoma. However, it has been studied for certain types of advanced melanoma.3 National cancer guidelines suggest it as one option when other treatments are not working.1 Generic forms of imatinib are available.

How does Gleevec work?

Gleevec is a type of medication called a kinase inhibitor. It works by blocking a receptor called c-KIT.

The c-KIT receptor is in the cell membrane (wall) of many different cells.4 In normal cells, a signaling molecule called “Stem Cell Factor” binds (connects) to c-KIT.4 This action sets a chain of events in motion. These events allow cells to grow and survive. Stem Cell Factor acts like a switch. It turns on the chain of events only when it is needed. This mechanism helps to keep cell processes under control.

C-KIT Pathway

Normal KIT signaling

Mutations cause c-KIT to act abnormally. C-KIT may start the chain of events without Stem Cell Factor. This leads to uncontrolled cell growth, which is when cancer develops. C-KIT mutations are found in:

  • 10% to 20% of melanoma on the fingers, toes, palms, and soles (acral melanoma)5
  • 15% to 20% of melanoma on the membranes that line the mouth, throat, nose, vagina, and anus (mucosal melanoma)5

Gleevec blocks (inhibits) c-KIT.2 Using Gleevec to treat melanoma cells with a c-KIT mutation slows cell growth and increases cell death.3 Gleevec is called a targeted therapy because it targets one feature that makes cancer cells different from normal cells.

Cancer cells can also have too many copies of the c-KIT genes (instructions). Having too many copies is called “amplification.” Gleevec does not work as well in cancer cells with c-KIT amplification.3

How effective is Gleevec for melanoma?

Gleevec was studied in a small group of people with melanoma and c-KIT mutation.3 About half (54%) had a partial response to Gleevec. “Response” has to do with whether the tumor shrinks or grows more slowly while on treatment. Response to treatment can be partial or complete. Response is only about tumor changes and it does not measure whether you—as a whole patient—have improved. Response is also different from survival.

Another 23% of people with c-KIT mutation had stable disease while being treated with Gleevec. Stable disease means that the cancer did not get worse or better.3

Eventually, the cancer progressed in nearly everyone (92%). The median time until the cancer progression was 3.9 months. The median overall survival was 12.9 months.3

How do I take Gleevec?

Before taking Gleevec, read the Medication Guide that comes in the package. Follow your doctor’s instructions for taking Gleevec.

Gleevec comes as tablets. Your doctor will tell you how often to take the medication. It may be once or twice per day.2 Take Gleevec by mouth with a meal and glass of water. Taking the medication with food reduces irritation to your stomach or intestine. If you cannot swallow a tablet, you can dissolve it in 2 to 4 ounces of apple juice or water.

For approved uses (indications), Gleevec is taken until the cancer progresses or the side effects are unacceptable.2 Ask your doctor how long you should take Gleevec. Talk with your doctor before stopping any medication.

What are the side effects of Gleevec?

Nearly everyone experiences side effects with Gleevec. The most common side effects of Gleevec in patients with melanoma are:3

  • Nausea and vomiting
  • Fatigue
  • Low red blood cell count (anemia)
  • High blood sugar (hyperglycemia)

Other common side effects are:6

  • Swelling and fluid retention (may be serious)
  • Muscle cramps or pain
  • Bone pain
  • Abdominal pain
  • Loss of appetite
  • Diarrhea
  • Abnormal bleeding (may be severe)
  • Rash, blistering, or other skin reaction

Less common but serious side effects of Gleevec are:6

  • Low blood cell counts
  • Congestive heart failure
  • Severe liver problems
  • Low levels of thyroid hormone
  • Electrolyte disturbance

Who should not take Gleevec?

Pregnant women should not take Gleevec.2 Women who could become pregnant should use highly effective birth control during treatment. Continue using birth control for at least 14 days after the last dose of Gleevec. Do not breastfeed while taking Gleevec. Do not breastfeed for 1 month after your last dose of Gleevec.

Tell your doctor about any medical conditions you have, especially: 6

  • Heart disease
  • Current or past kidney failure
  • Thyroid problems
  • Eye problems
  • Liver problems
  • Muscle problems

Tell your doctor about all the prescription and non-prescription medications and supplements that you take. The coating for Gleevec contains iron. Tell your doctor if you take or are planning to take a supplement with iron.

What precautions are needed when taking Gleevec?

Use caution when driving a car or operating machinery. Side effects of Gleevec include dizziness, blurred vision, or drowsiness. Patients have reported motor vehicle accidents while using Gleevec.6

Avoid grapefruit juice and other foods that affect the way Gleevec works.2

Use highly effective birth control during treatment and for at least 14 days after the last dose of Gleevec if you could become pregnant.2 Do not breastfeed during treatment with Gleevec or for 1 month after.2

Written by: Sarah O'Brien | Last reviewed: May 2017.
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